Some embodiments described herein relate generally to methods and apparatus for enabling efficient multicast data traffic flow. In particular, but not by way of limitation, some embodiments described herein relate to methods and apparatus for defining multicast virtual local area networks (mVLANs) by grouping individual VLANs and defining multicast tunnels associated with the mVLANs.
In some converged networks, unicast tunnels are established between the core network node and each access network node. In large campus or enterprise networks, thousands of access network nodes and multiple client devices that subscribe to the same native multicast group. In such cases, the core network node sends a copy of the multicast data unit via the unicast tunnel to each access network node that is coupled to client devices that subscribe to the native multicast group. All the unicast tunnels, however, are constructed over the same physical network infrastructure of the campus network. Hence, thousands of copies of the same data unit can traverse over the same physical links, thereby significantly wasting bandwidth in the campus network. Additionally, making thousands of copies of a data unit requires increased processing power at the core network node.
Additionally, the multicast forwarding rules are produced at the core network node on per-VLAN basis as the client devices in the VLAN subscribe to the native multicast group. A copy of the multicast data unit is made for each VLAN at the core network node. Typically, most large campus or enterprise networks have thousands of VLANs. Hence, a copy of the multicast data unit per VLAN (among thousands of VLANs) traversing over thousands of unicast tunnels compounds the problem of extremely high computational demands and bandwidth wastage on the infrastructure of a campus or enterprise network.
Known methods for overcoming bandwidth demand problems in campus networks include defining a single default multicast tunnel statically from the core network node to all access network nodes. In such methods, the core network node sends all the multicast traffic into the default multicast tunnel. One drawback of such method is that the multicast traffic reaches all the access network nodes regardless of whether or not any client devices associated with an access network node subscribed to the native multicast group. Additionally, the multicast forwarding in such methods is not virtual router (or anchor) specific. Hence, client devices can possibly receive multicast traffic from sources in other virtual routers. This can lead to unnecessary use of computational resources and wastage of bandwidth in a campus or enterprise network.
Accordingly, a need exists for methods and apparatus that can enable efficient multicast traffic flow that can significantly reduce bandwidth wastage and can significantly reduce high computational demands on the core network nodes.